A Case-Control Study Investigating the Relationship between Vitamin D Levels and Upper Urinary Tract Infections (UTIs) in Children between 2 Months and 6 Years Old in Selected Hospitals of Iran University of Medical Sciences in 2021

Urinary tract infection in children has a high prevalence and can cause high complications and morbidities. In general, UTIs are among the rising infections. Bacteria originating from fecal flora are colonized in the perineum and enter the bladder through the urethra. In some cases, the bacteria causing cystitis go to the kidneys and cause pyelonephritis. If bacteria reach the kidney from the bladder, they can cause acute pyelonephritis. The lack of micronutrients in children is considered a challenge in the health system of most countries. Vitamin D or its active form (D3) or 25-OH-Vit-D is a fat-soluble vitamin that can be stored in the body and helps the growth and strength of bones by controlling the balance of calcium and phosphorus. A severe Define vitamin D can lead to osteoporosis and soft bones (rickets). Weakness of the immune system, seasonal depression, autoimmune disease, skin problems such as eczema and psoriasis, and mood swings are other problems related to vitamin D deficiency in the body. Although vitamin D deficiency plays a role in the occurrence of various diseases, recent studies have reported that since vitamin D plays an important role in strengthening the immune system, a decrease in its serum level can lead to the occurrence of various infectious diseases of bacterial and viral origin. For this reason, according to the prevalence of UTI, some researchers stated that vitamin D deficiency can be considered as an important risk factor in the occurrence of this infection in children, which requires more studies. In addition, according to some studies, vitamin D can improve the immune system and reduce the possibility of urinary tract infections. But this effect has not been definitely determined, and on the other hand, the use of vitamin D supplements is sometimes one of the factors that cause kidney stones, although vitamin D deficiency plays a role in the occurrence of various diseases, recent studies reported that since vitamin D plays an important role in strengthens the body's immune system, reducing its serum level can provide the basis for the occurrence of various infectious diseases of bacterial and viral origin. Therefore, considering the importance of this issue, the purpose of this study is to investigate the relationship between the level of vitamin D and infections Upper urinary tract infection (UTI) in children between 2 months and 6 years in selected hospitals of Iran University of Medical Sciences in 2022.

The present study was conducted with the aim of investigating the relationship between vitamin D level and upper urinary tract infection (UTI) in children between 2 months and 6 years old in selected hospitals of Iran University of Medical Sciences in 2022. This studywas conducted on 50 children with the first episode of febrile UTI and 50 normal children without UTI aged 2 months to 6 years who Were visited in Ali Asghar Hospital. Sampling was done by simple random method. The inclusion criteria for children with UTI included: (1) signs and symptoms of the disease, including the presence of fever (greater than or equal to 38 degrees), abdominal pain, dysuria, anorexia and nausea, 2) pyuria, (3) positive urine culture, (4) no history of taking vitamin D supplements during the last 12 months(Even prophylactic vitamin D supplement (400IU/day) (5) no malnutrition or obesity, and (6) no kidney disorders. Patients with the following symptoms were excluded from the study: (1) positive culture for more than one organism, (2) history of any infection or systemic disease such as diabetes, immune system deficiency, symptoms of osteoporosis and hypertension, (3) patients with congenital defects including renal and urinary tract disorders, neurogenic bladder, urinary stones, chronic renal failure, and (4) a history of VUR. The results of this research were analyzed by SPSS software. Quantitative data were reported as mean ± SD and median and interquartile range. Qualitative data were reported as numbers and percentages. The mean of parametric data was compared between two groups using independent sample-t test if normality was established, otherwise it was investigated using non-parametric test. Also, the effect of independent variables on the incidence of UTI was investigated using multinominal regression. In this study, p value equal to or less than 0.05 was considered statistically significant. In this study, all patient information is confidential and their names and addresses will never be mentioned. Also, this plan was first proposed in the Ethics Committee of Iran University of Medical Sciences and after its approval, it started in this committee. The information of the patients was coded. After selecting the patient and control groups based on the study inclusion criteria, a checklist was prepared in which the demographic information of the individuals, including age and sex, was recorded. Also, the results related to the analysis of routine laboratory tests such as CBC, WBC, PMN, ESR, and CRP, BUN, ALP, calcium and blood phosphorus were also measured and recorded for the patients.

In this study, 55 patients from the case group (with UTI) and 54 patients from the control group (without UTI) were examined. 7 patients with abnormal kidney and urinary tract ultrasound were excluded from the case group, and finally 48 patients from this group were examined. Using the Kolmograf Smirnov test, the distribution of patients' tests was measured and it was found that none of them follow a normal distribution. Therefore, to describe the tests of the patients, the interquartile range and the median were used. Using the non-parametric MANN-WHITNEY test, it was found that vitamin D has a significant difference in the two groups, and it is significantly less in the case group (with UTI). P=0.041). After taking into account the lack of vitamin D level of less than 30 nmol/liter, the Odds Ratio equal to 2 was calculated regarding the lack of vitamin D level and the possibility of developing UTI, and in other words, vitamin D deficiency doubles the chance of developing UTI. However, it was found that vitamin D had no significant relationship with gender in any of the groups (P=0.422, 0.847). Age in the control group was not significantly related to vitamin D level (P=0.188, 0.143). Also, using Spearman's test, the relationship between vitamin D level and other tests of patients was also measured and it was found that in none of the groups, vitamin D level had no significant relationship with other tests.

In the present study, it was found that the level of vitamin D is significantly lower in Children aged 2months to 6 years with UTI. However, there was no significant relationship between vitamin D level and gender and age. Also, vitamin D level was not significantly related to other tests including WBC, PMN, creatinine, BUN, ESR, CRP, alkaline phosphatase, phosphorus, and calcium in any of the groups. In addition, it was found that vitamin D deficiency (less than 30 nmol/liter) doubles the chance of UTI. Since vitamin D levels were found to be lower in people with UTI, it seems that taking vitamin D supplements can reduce the incidence of UTI.